Brian May's Deacy Amp secrets revealed  [traced]

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Brian May's Deacy Amp secrets revealed

Postby vanessa » 20 Aug 2007, 23:07

I know it's an amp of sorts, but in a way it's really a 9V effect used in recording. I post here because I've seen that there is someone "boutique" store that's selling clones for like $1500 or some fool nonsense.

Well I did a few (obsessive) months research on this little puppy I even bought a VOX "reissue" and gutted it to make certain comparisons about hunches I had.
With all the info I dug up, I'm 100% convinced that the Deacy Amp that Brian May used on many a recording for Queen was one of two portable radios quite common in the UK that ran off a 9V battery supply. It was in fact not a car radio that John Deacon claimed he thought it to be. He found a gutted radio in a "skip" and this circuit was used to make the amp. I did a ton of research on that theory and it does not hold water (based off of all the car radios designed in the period of about 10-15 years prior). I also came across a schematic that (everyone has this who's on the hunt) is claimed to be the Deacy amp and proves this theory also to be untrue.

The new reissue is a far cry from the original radio power amp design but is very similar in its layout and its adaptation of this old circuit to newer IC technology. The old design used hard to find (not really, I'll tell you later) low wound transformers.

Out of the two portable radio units I found to be identical to the Deacy (either could be used for a clone) the one that won out as to where the guts came from to make the Deacy amp was.... (drum roll please)

The Roberts R200/R300 series 9V battery portable radio. The other that is almost identical (but was ruled out because it's point to point) is the Bush (I've got the model #, I forgot it, I'll post it later. Bushmaster?) 9V.

But there are a ton that you could build this from, this was the most common transistor radio circuit of the late 50's to mid 60's. American (I used an old 50's RCA that had the exact circuit in it), Japanese, Euro, etc., etc... No need to search all over hill and dale for transformers. Go to the local junkyard and buy any broken 9V radio from the period and you got the two that you need. Or just use the whole circuit and just plugin...

Use an old house speaker, or find a "whizzer cone" speaker (to be exact) and build a little cab for it and this and break out those old Queen albums to play along. Better yet get an old Pignose 9V amp, the circuits are almost identical and break out those old Zappa albums...
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Postby modman » 21 Aug 2007, 00:46

vanessa wrote:Go to the local junkyard and buy any broken 9V radio from the period and you got the two that you need. Or just use the whole circuit and just plugin...

Wow, Van, great project! Talk about pedals for proles...Any 9V radio?
But where do I plug into exactly?
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Postby vanessa » 21 Aug 2007, 01:26

modman wrote:
vanessa wrote:Go to the local junkyard and buy any broken 9V radio from the period and you got the two that you need. Or just use the whole circuit and just plugin...

Wow, Van, great project! Talk about pedals for proles...Any 9V radio?
But where do I plug into exactly?


I'll post the schematic later tonight. You just need to splice into the power amp section of just about any of the early germanium transistor/transformer based 9V radios and then run the output into an old home speaker (the more crap the better).
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Postby soulsonic » 21 Aug 2007, 01:51

This sounds fun..... I just tore apart a little transistor radio like this a couple months ago to get the germanium transistors out of it (got some good ones too). I still have the circuit board and it indeed has a couple small audio transformers in it so it may be just right for a Deacy.
Funny how synchronicity works...
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Postby RLBJR65 » 21 Aug 2007, 12:45

Thanks Vannessa!
Looks like I'll have to hit some thrift stores :D

These are the trany specs if anyone is interested.
Colne 06005 (Hammond 57318) 3.5:1 + 1, Primary Rp 130 ohms, secondarys Rs 40 ohms.
Colne 06006 (Hammond 57319) 3.1 + 3.1:1, Primarys Rp 1 ohm, secondary Rs 0.2 ohm.
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Brian May's Deacy Amp secrets revealed  [traced]

Postby vanessa » 21 Aug 2007, 15:18

I think most on the hunt have this. But I 'll post anyway. This is supposed to be the schematic for the Deacy. It seems to check out. I'll post the full radio version if I can find
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Postby vanessa » 21 Aug 2007, 15:25

This is the radio I'm convinced the Deacy was taken from:

Roberts R200/R300


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Postby markm » 21 Aug 2007, 15:39

Very Cool.
Never heard of those radios here.
Thanks Van! 8)
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Postby vanessa » 21 Aug 2007, 16:27

markm wrote:Very Cool.
Never heard of those radios here.
Thanks Van! 8)


They are very collectible. You would need to find a broken or a esthetically bad one to feel the need to rip one apart for a Deacy amp. But it's all there, ripe for a Deacy amp. (If I had a really nice one I would keep it. They look really cool, and are worth some money).

Better would be to look into other options. In the USA RCA and others (Japanese) radios are a plenty up on ebay. The shipping alone on a Roberts to the USA is prohibitive.

You'll find Roberts radios mostly in the UK/Europe and sometime NZ, AU.
The other exact circuit is the Bush, I believe the Bushmaster. But it uses a steel chassis with point to point wiring. You can use it too (my old RCA is much the same), but it is said that the Deacy amp's components lay on a PCB, not point to point.
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Postby vanessa » 21 Aug 2007, 16:31

I will add that what ever you use to build one there is a front section [pre power amp] of parts that will be left over.
I've seen OC44, NKT275, OC81, etc.. in these units. Also paper in oil caps and a whole lot of other goodies that can be salvaged from that front section.
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Postby vanessa » 21 Aug 2007, 16:33

Bush, Bushmaster:

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Postby markm » 21 Aug 2007, 16:49

Just the look of these things alone are very appealing to me.
Very Retro! 8)
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Postby vanessa » 21 Aug 2007, 17:10

markm wrote:Just the look of these things alone are very appealing to me.
Very Retro! 8)


I know what you mean. I bought up a few vintage radios over a period to make a Deacy amp and the reason I bought a few was I just could not get myself to destroy them for this project. In the end the RCA I bought for it was completely dead and beyond repair.
It's shell has a similar look as these do. I'm going to convert the shell into a studio "mono reference" speaker (for mix downs) using a mosfet booster as its power amp. It looks very retro and it will be state-of-the-art functional in my home studio.

8)
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Postby briggs » 21 Aug 2007, 17:40

I have an original bush, bushmaster. My mother gave it to me.....
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Postby analogguru » 21 Aug 2007, 18:14

I read about this "secret weapon" amplifier long time ago. There wer not much informations more than it should have had approx. 1W output power.

Since the principle of this power-amp was used from the 50´s until the late 70´s - you could find it in every radio and disc-player - it would be interesting, when this "secret weapon" should have been built.

I doubt that therewas used one of the old 50´s radios since there were more modern parts available for a reasonable price.

Even the circuit has been "modernized" using an NTC or a diode between base-bias and ground for temperature compensation.

So any more information on this "secret weapon" would be apreciated.

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Postby vanessa » 21 Aug 2007, 19:22

analogguru wrote:
So any more information on this "secret weapon" would be apreciated.

analogguru



The story goes that in the early/mid 1971 John Deacon of Queen found what he believed (or wanted others to believe) to be the circuit board of a car radio in a garbage dumpster. He took it home, messed with it, and found it made a nice little guitar amp using a junk home stereo speaker with a 9V battery.
He then showed Brian May the amp, but when Brian played it he did not like the sound of it (impedance mismatch could have been to blame). For the heck of it he plugged a Rangemaster in front of it and the little amp "came alive".

This is the amp responsible for a lot of what you hear on all the Queen albums. Even the wah-wah parts (what you think are) are just this little amp mic'd and turned speaker facing ceiling with a pillow over it. You move the pillow up and down for a wah-wah effect. For that "parked wah" effect that you here on stuff like the solo for "Bohemian Rhapsody" that's this little amp. It just sounds like that when mic'd to tape. The big guitar sounds of the rock'n bridge are cranked VOX AC30's (with Rangemaster) layered in with this little amp as well.

Later it is said he used his si May booster with this amp. I think this to be wrong. I believe he used a stock Rangemaster for all the studio stuff over the span of all the Queen records. The proof is the tone never changed.
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Postby Mayniac » 21 Aug 2007, 23:42

vanessa wrote:For that "parked wah" effect that you here on stuff like the solo for "Bohemian Rhapsody" that's this little amp. It just sounds like that when mic'd to tape. .

Hmmm.... I don't know about that... For the Bohemian Rhapsody solo he used one of the out-of-phase settings of the Red Special, which generates this piercing solo sound. The extra 'phasing' effect is said to be added later in the studio. However, I don't know whether the Deacy amp was used. As far as I know, the main use for the Deacy amp is the multi-layer stuff (think Wedding March, Procession, etc..), but it's probably used whenever it sounded cool to him.

vanessa wrote:Later it is said he used his si May booster with this amp. I think this to be wrong. I believe he used a stock Rangemaster for all the studio stuff over the span of all the Queen records. The proof is the tone never changed.

I'm pretty sure this is not true. Brian lost the Rangemaster at a gig during the early years. From then on, he used a treble booster, built by either his father or later Pete Cornish (don't remember the details right now). The Pete Cornish one is certainly si. I think you can hear this subtle change in sound, as IMHO from the 3rd album on the guitar sounds are a little less raw or gritty, compared to the first 2 albums. On the other hand, this could also be due to use of different recording techniques...
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Postby vanessa » 22 Aug 2007, 00:05

Mayniac wrote:
vanessa wrote:For that "parked wah" effect that you here on stuff like the solo for "Bohemian Rhapsody" that's this little amp. It just sounds like that when mic'd to tape. .

Hmmm.... I don't know about that... For the Bohemian Rhapsody solo he used one of the out-of-phase settings of the Red Special, which generates this piercing solo sound. The extra 'phasing' effect is said to be added later in the studio. However, I don't know whether the Deacy amp was used. As far as I know, the main use for the Deacy amp is the multi-layer stuff (think Wedding March, Procession, etc..), but it's probably used whenever it sounded cool to him.


You may be right, I was not there. But I have built one of these and yes I did the out-of-phase trick (Classic Albums DVD) with the neck and center pups and it was as dead on as it gets.

Mayniac wrote:
vanessa wrote:Later it is said he used his si May booster with this amp. I think this to be wrong. I believe he used a stock Rangemaster for all the studio stuff over the span of all the Queen records. The proof is the tone never changed.

I'm pretty sure this is not true. Brian lost the Rangemaster at a gig during the early years. From then on, he probably used a si treble booster, built by either his father or later Pete Cornish (don't remember the details right now). The Pete Cornish one is certainly si. I think you can hear this subtle change in sound, as IMHO from the 3rd album on the guitar sounds are a little less raw or gritty, compared to the first 2 albums. On the other hand, this could also be due to use of different recording techniques...


I would find it hard to believe that May could not find a replacement Rangemaster especially when it was so key to their sound and when it was "thee" pedal that worked with the Deacy. When you talk about the Si May boost you make it sound like it's less gritty than a Rangemaster. I've found them to be exactly the opposite of your description. the May Boost is completely insane by comparison (I think anyway). Way more gain and volume than a Rangemaster. I would not rule out its use on AC30 for the later albums but it does not sound like it was put to use on the Deacy.

BTW, I've read some downplay the Deacy's use in the studio (I think they want you to buy signature VOX AC30's). I've also read it was used on almost everything. Build one and decide for yourself.
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Postby analogguru » 22 Aug 2007, 00:41

Funny, how the history is "bended" and everybody claims something. So many battery powered amplifiers....Here:
http://www.petecornish.co.uk/queen.html
you can read Pete Cornish´s version:

Although I cannot be sure of the date (possibly 1973/4), during my tenure as Chief Engineer at the Sound City group of companies, I was asked to build a small, battery powered amplifier to be used with the treble boost for recording. I built this amp from parts obtained locally in Soho - Lisle Street was a very good source of electronic components in the early 70's - but sadly all details of this amp were lost when the Cities Group closed in July 1975.


Here
http://www.brianmaycentral.net/sounds.html
you can read:
Brian also uses a small amplifier in the studio, which was built by Queen's bassist, John Deacon. This amp is affectionately known as the Deacy amp. Brian used this amplifier to produce many of the 'guitar orchestrations' which have become part of his trademark sound. This amplifier is often overlooked, but it undoubtedly contributed substantially to many classic Queen tracks. It is a solid state (germanium transistor) combo amp with a small speaker, which John adapted from a hi-fi amp and speaker that he rescued from a skip!


Hmmm..... John Deacon was contracted as a bassist in 1971....
Sorry, that I don´t believe the Roberts/Bush radio-story with OC-trannies.

We know that the amp should handle 1W, but not with this 2 OC81-trannies.

Greg Fryer reports here:
http://www.brianmay.com/brian/briannews ... jun05.html

John literally found the circuit board as he was walking down the street one day in London - this occurred in early/mid 1971 at a time when he was first playing in "Queen" with Freddie Mercury, Roger Taylor and Brian May.


This could have also been the Edgware Road or the Tottenham Court Road - both were miles of electroinic-shops

Being a keen electronics experimenter (and was then studying for an Electronics Degree), John's attention was drawn to the wires that were dangling over the side of a builder's skip - the large skip was sitting on the side of the road filled with rubbish which was about to be taken away to the tip.

These wires were attached to a circuit board and John's curiosity led him to examine the board to see if he could salvage it and put it to some use. He initially thought that the circuit board might have come from a battery operated cassette player or radio, and after inspecting it decided it would do the job as a small practice amplifier for guitar (John played guitar as well as bass).


So there never has been a cassette player with OC-trannies, it must be something more "fresh".

John coupled the newly found circuit board with a spare bookshelf speaker box that he had lying around - the circuit board was fixed inside the speaker box with two screws


If this would be one of the old radios boards this would be nearly impossible

and the finished product featured only the most spartan of controls:

On the back panel of the speaker box was fitted a single jack socket to plug the guitar lead into - the amp's power was turned on by simply connecting the two battery clip leads (which came out from the back panel) to a large PP9 battery - and through most of its history the Deacy Amp has had no volume or tone controls whatsoever although John remembers that initially he rigged up a volume control which hung loose outside the speaker box - soon after he fixed the volume internally on full, having found that this sounded best - there were definitely no deluxe frills with this model!

With a standard guitar plugged in, John said the amp possessed a warm and pleasant (and partly distorted) sound but lacked brilliance or much definition - however a new way of using this little amplifier was about to be found that would change its sound and make it an invaluable part of Queen's recording armoury...

By some chance John brought his practice amplifier along to band rehearsal one day and showed it to Brian - immediately he said, Brian was interested in the amp's possibilities - and especially so when he heard how it behaved once he plugged in his innovative home made Red Special guitar and Treble Booster pedal.

These two changed the amp's sound dramatically, overdriving both the input and output stages and producing a richly distorted but defined and sustained sound which resembled such things as violins, cellos and even vocals.

John commented that the rich saturated compressed type of distortion produced by the combination of Red Special guitar, Treble Booster and Deacy Amp was very unique and different to the more typical harder sounding "sawtooth waveform" distortion common at the time in many guitar effects and amps.

He mentioned that the recording engineers that the band were working with particularly liked the way the amp behaved in the recording studio. Here the amp would produce a constant response, whereas the engineers found it more difficult to capture on tape the exciting and dynamic sound of Brian's Vox AC30 amps.

John's small amplifier became known as the "Deacy Amp", and featured regularly on Queen albums where Brian used it for his creative, highly original "Guitar Orchestration" multi-tracked pieces. These were painstakingly built up line by line (and even note by note on some of the more complex pieces such as "Good Company" from Night at the Opera). Although the Deacy Amp is a deceptively simple looking piece of equipment, the wide number of creative uses that Brian has managed to find for this little piece of rock history is nothing short of remarkable.

On occasions Brian's Vox AC30 was combined on tape with the Deacy Amp but usually on Queen records it was just the Deacy Amp alone used for the multi-tracked guitar orchestrations. Brian has described the way that the Deacy Amp's sounds sit and blend together when recorded as being "symphonic" compared to other amps used for this purpose, whereas when the AC30 was tried its combined sounds didn't have the same character and effect.

The tracks "Procession" and "The Fairy Feller's Master-Stroke" from the album "Queen II" (released in March 1974) saw the first recorded examples on a Queen album of the Deacy Amp.

Perhaps the best known example of the amp's use is "God Save The Queen" from 1975's "A Night At The Opera", whilst possibly the most unusual use was for all of the jazz band sounds on the song "Good Company" (trombones, clarinets and all!), from "A Night At The Opera".

The Legendary Deacy Amp continues to this day in good health and continues to occupy an important place in Brian May's recording studio.


Hey, interesting... why are then so many rumours about that ?

Now we listen to the truth:

Technical Background of the Deacy Amp

In early 1998 Brian May asked me to take apart, photograph and document all aspects of the Deacy Amp's circuit board, components and speaker box. This work was conducted at Brian's Allerton Hill studio with the valuable assistance of Pete Malandrone during the time that I was restoring Brian's famous Red Special guitar.

Deacy Amp Circuit Overview:

The Deacy Amp circuit is a 1950s audio style Germanium transistor push-pull circuit, utilising in its front end an AC125 and AC126 respectively, with the push-pull Output stage comprising two AC128 Germanium transistors.


Yes this listens better.... for that period of time a standard circuit...even used in many japanese radios....

But I am pretty sure it had a temperature stabilization....

It also features a Driver Transformer and an Output Transformer and is similar to several designs of the time, which can be found in the Mullard Reference Manual of Transistor Circuits (see pages 168, 170 and 171).

John Deacon slightly altered the front end of the amp to allow it to better suit guitar frequencies, and it will be amusing to many people to learn that this design had been originally created to run cleanly and undistorted in audio use - a very far cry from the way Brian May turbo-charged the little amp for guitar use!

The speaker box contains a 6.5" 4 ohm twin cone driver speaker and a small tweeter speaker which is no longer working The Deacy Amp is powered by a large 9 volt PP9 battery and its power output is approx one watt.


Funny....here:
http://www1.gitarrebass.de/magazine/0307/vox.htm
we can read
that it was only 0,45W
... what was a normal value for two AC 128 running on 7,5V like in this early philips cassette players:

http://i21.ebayimg.com/02/i/000/ae/bd/f12e_1.JPG

here more info:
http://www.vintage-radio.com/manufactur ... annie.html

Also interesting to read:

...Vox and their technician Steve Grindrod...


Hey....I know Steve from the time when he was working for Marshall, at the end of the 80´s he was working (secretly?) for Vox and then again for Marshall... Now he seems to be working again for Vox....

And also interesting to read the "car-radio"-story....
Yes this time there were cars running on 6V only..... and some had 12V
But if there were used transistors in a car-radio then it would be AD161/162 for the power stage... and neither OC81 nor AC128.

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Last edited by analogguru on 22 Aug 2007, 01:26, edited 2 times in total.
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Postby soulsonic » 22 Aug 2007, 01:02

Hey AG, the little transistor radio I have matches your description almost exactly with having basically the same topology as Vanessa's schematic, but using the type of transistors you've described.
The radio is a "North American 15 Transistor Solid State" pocket radio made in Hong Kong. It was full of nice Toshiba 2SA... type germanium transistors and I got about 10 usable ones out of it.
I guess I'll have to repopulate the power amp section of the board with some AC128s and see what happens.
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